1. Field of the Invention
The present invention relates to a minimally invasive, continuous monitoring technology for monitoring the concentration of body constituents, which can be useful to help maintain a person's or animal's well being and for treating certain diseases. Notable examples of constituents that may be monitored include: blood glucose, oxygenated hemoglobin, electrolytes, drug and toxic agent levels, bilirubin, etc.
For simplicity, the invention is described in the context of monitoring of blood glucose concentration. However, the invention can be similarly used for monitoring the concentrations of other body constituents.
2. Background of Glucose Monitoring
Diabetes is the fastest growing serious illness in the western world. In the US and Europe there are well over 40 million people suffering from diabetes (see reference #1, identified below). Diabetes that is characterized by elevated blood glucose levels is associated with numerous severe pathologies that are responsible for serious clinical manifestations in many of the body systems, for example, cardiovascular, neurological, renal, ophthalmic etc (see references #28-31, identified below). The unstable blood glucose level may also result in life threatening hypoglycemia.
Many of the medical complications associated with diabetes can be reduced and even prevented by strict control of the blood glucose level. However, this requires frequent measurement or monitoring of the blood glucose level and, on this basis, the introduction of the appropriate treatment. The treatment may range from diet to insulin injections or delivery by pumps. Unfortunately, conventional blood glucose concentration measurements require blood drawing. And because it is painful, many patients do not make the measurements as often as they should. As a result, they may not control their glucose level well enough and complications are quite common.
One prior art solution to this problem is to implant continuously monitoring sensors that are inserted into the body by means of a small bore needle (penetrating rather deep under the skin) and connected to an outside device by wire leads. But the use of such devices is thus far very limited.